A Highly Divergent Synthesis of 3-Aminotetrahydropyridines.

Dihapto-coordinate 1,2-dihydropyridine complexes of the metal fragment {WTp(NO)(PMe3)} (Tp = tris(pyrazolyl)borate), derived from pyridine, are demonstrated to undergo protonation at C6 followed by regioselective amination at C5 with a variety of primary and secondary amines. The addition takes place stereoselectively anti to the metal center, producing exclusively cis-disubstituted products. The resulting 1,2,5,6-tetrahydropyridines can be successfully liberated by oxidation, providing a route to novel molecules of potential medicinal interest.